[LeetCode][Python3] 617. Merge Two Binary Trees

Problem :

https://leetcode.com/problems/merge-two-binary-trees/description/

My Solution :

# Definition for a binary tree node.

# class TreeNode:

# def __init__(self, x):

# self.val = x

# self.left = None

# self.right = None

class Solution:

def mergeTrees(self, t1, t2):

"""

:type t1: TreeNode

:type t2: TreeNode

:rtype: TreeNode

"""

if t1 and t2:

t1.val += t2.val

t1.left = self.mergeTrees(t1.left, t2.left)

t1.right = self.mergeTrees(t1.right, t2.right)

else:

t1 = t1 or t2

return t1

Comment :

새로운 Tree를 만들지 않고 그냥 recursion 하면서 t1에다 val이나 reference를 update 치는 방식으로 구현하였다.